Peak amps are not a measurement. No standard governs the figure printed on a lithium jump starter. Here are 2 listings from this page, in the makers' own words:
The cheapest unit here claims 30 % more diesel than the dearest one. One of those numbers is not a measurement, and the page does not decide which: it puts the columns side by side and lets you look. 2 makers here now advertise honest specifications as a feature — which tells you what the norm has become.
The cold is the real problem, and one maker out of 17 publishes a temperature. AstroAI says −20 to 50 °C. Everyone else is silent. In cold, the engine needs more current — thick oil, and a diesel runs its glow plugs first — while every battery delivers less, the car's and the jump starter's alike.
So: keep it in the house, not in the trunk. A pack stored at −25 °C is the one that will not work the morning you need it. That single habit matters more than any figure in the table below.
One last thing: the tiers are my judgement, not the makers' promise. A cheap unit claiming a 6 L diesel is filed under gas cars. The table shows what it claims; the tier says where I would put it. The gap between the 2 is the subject of this page.
For a gas car
A sedan, a compact, a 4-cylinder. The most common case, and the one that asks the least. Notice the gap between what these 3 cost and what they claim to start.
| Model | Claimed peak | Engine claimed by the maker | Recharge | Inflator |
|---|---|---|---|---|
| NOCO Boost GB20 | 500 A | 4,0 L essence | USB-C | no |
| GOOLOO GP2000 | 2 000 A | 8,0 L ess. / 6,0 L diesel | USB-C | no |
| AstroAI with compressor | 4 000 A | tous ess. / 10 L diesel | charge rapide | yes |
NOCO Boost GB20
500 A · essence jusqu'à 4,0 L · USB-C
The most modest unit here, and the only figure that is not trying to impress. NOCO claims 500 amps and declines to claim any diesel — which is a way of saying it starts none. For a compact that is exactly right, and the restraint is what makes the rest of their numbers believable.
GOOLOO GP2000
2 000 A annoncés · 500 g · USB-C
Half a kilo, and it claims a 6 L diesel — more than a far dearer NOCO. Take it for what it is: a good small unit for a gas car, well built, fairly priced. It is the printed promise that is generous, not the object.
AstroAI with compressor
4 000 A annoncés · gonfleur 150 psi · −20 à 50 °C
The cheapest item here, and still the only one of the 17 to publish a temperature range: −20 to 50 °C. That candour is worth more than the 4,000 amps printed beside it. It also inflates tires, which makes it the best value of the lot — provided you remember that −20 °C, here, is an ordinary January night.
For a pickup, an SUV, a V8
More displacement means more current at the starter, and a bigger battery to revive. This is where real capacity starts to matter more than peak amps: not for the first attempt, but for the fifth.
| Model | Claimed peak | Engine claimed by the maker | Recharge | Inflator |
|---|---|---|---|---|
| NOCO Boost GB40 | 1 000 A | 6,0 L ess. / 3,0 L diesel | USB-C | no |
| NOCO Boost X GBX45 | 1 250 A | 6,5 L ess. / 4,0 L diesel | USB-C 60 W, 48 min | no |
| GOOLOO GP4000 | 4 000 A | tous ess. / 10,0 L diesel | USB-C | no |
| VTOMAN V10 Pro | 4 500 A | tous ess. / 10,0 L diesel | USB-C 15 W | no |
NOCO Boost GB40
1 000 A · 6,0 L essence / 3,0 L diesel · 20 démarrages
The one I would keep if I kept only one. NOCO claims 20 starts per charge, which is the figure that actually matters: a unit that starts once and then quits will not get you out of a sloped parking lot on a Sunday night.
NOCO Boost X GBX45
1 250 A · 6,5 L / 4,0 L · recharge en 48 min
48 minutes for a full USB-C recharge, and 60 W out for a phone. Fast charging is not a gimmick in winter: it is what lets you put it back in service the same evening, instead of leaving it half full until the next failure.
GOOLOO GP4000
4 000 A annoncés · « tous moteurs à essence »
4 000 amps claimed, and “all gas engines” with no displacement limit. A promise with no ceiling is not a specification: a specification stops somewhere. That said, the unit is solid and its listing does mention cold, which most do not.
VTOMAN V10 Pro
4 500 A annoncés · USB-C · lampe d'urgence
The highest claimed peak on the page, on the cheapest unit in its tier. VTOMAN writes “a true 4,500 amps”, which is telling in itself: when a maker has to specify that its number is real, the market has stopped believing the numbers.
For a diesel or a big engine
A diesel asks for 2 things before it even turns over: the glow plugs draw current for several seconds, then the starter attacks a much higher compression than a gas engine. The hardest case, and the one where an invented peak shows up immediately.
| Model | Claimed peak | Engine claimed by the maker | Recharge | Inflator |
|---|---|---|---|---|
| NOCO Boost GB50 | 1 500 A | 7,0 L ess. / 4,5 L diesel | USB-C | no |
| NOCO Boost X GBX75 | 2 500 A | 8,5 L ess. / 6,5 L diesel | USB-C 60 W, 1,8 h | no |
| NOCO Boost GB150 | 3 000 A | 9,0 L ess. / 7,0 L diesel | USB-C | no |
| GOOLOO GT4000S | 4 000 A | 12 L ess. / 10 L diesel | 100 W, 1,2 h | no |
NOCO Boost GB50
1 500 A · 7,0 L essence / 4,5 L diesel · 30 démarrages
30 starts per charge, and a diesel figure of 4.5 L. The first in the line I would put in front of a real pickup diesel. Note that NOCO goes from 1,000 to 1,500 amps to gain 1.5 L of diesel: that is what a coherent scale looks like.
NOCO Boost X GBX75
2 500 A · 8,5 L / 6,5 L · recharge en 1,8 h
2 500 amps for 6.5 L of diesel. Between the GB50 and this one, NOCO adds 1,000 amps and gains 2 L. The scale still holds — which is exactly what you cannot check with makers who print the same 4,000 A on every model.
NOCO Boost GB150
3 000 A · 9,0 L / 7,0 L · 80 démarrages
The biggest and the dearest here. 80 starts per charge: this is a shop's tool, a fleet's tool, or one for someone with a tractor and a generator on top of their vehicles. For a single car it is far too much.
GOOLOO GT4000S
4 000 A annoncés · recharge 100 W en 1,2 h
Its listing claims 12 L gas and 10 L diesel — the broadest promise on the page, far below the price of the GB150 that claims 7. What is verifiable here, though, is good: 100 W recharge in 1.2 hours and 24 months of standby. Buy it for that.
With a compressor — a flat tire is more common than a flat battery
In Quebec, between April's potholes and November's pressure drop, you inflate a tire more often than you revive a battery. A unit that does both earns its place in the trunk all year instead of sleeping there.
| Model | Claimed peak | Engine claimed by the maker | Recharge | Inflator |
|---|---|---|---|---|
| GOOLOO A3 | 3 000 A | 9,0 L ess. / 6,5 L diesel | USB-C | yes |
| GOOLOO A5 | 4 000 A | tous ess. / 10 L diesel | USB-C 45 W intégré | yes |
| VANTRUE POWER JS3 | 3 250 A | not published | USB-C 65 W | yes |
GOOLOO A3
3 000 A annoncés · gonfleur 150 psi · 5 modes
5 preset inflation modes — car, SUV, bike, ball — with automatic cutoff at the target pressure. That is the detail that makes it get used: an inflator you have to watch stops coming out of the trunk.
GOOLOO A5
gonfleur 160 psi · 20 000 mAh déclarés · USB-C intégré
This one deserves a note: its listing advertises “a true rated capacity of 20,000 mAh, honestly stated”. A maker selling the honesty of its own numbers as a feature tells you something about the category. The USB-C cable is built into the case, so it is never left behind.
VANTRUE POWER JS3
3 250 A annoncés · 160 psi · recharge 65 W
VANTRUE's title says “a true 3,250 A” and the listing promises “honest, real specifications without exaggeration”. The second maker here to turn restraint into a selling point. The odd number — 3,250 rather than 4,000 — is the kind of detail nobody invents.
What keeps you from needing one
Here is the part that costs me a commission, and I am keeping it anyway. A battery kept charged does not die. A maintainer, plugged into the wall and clipped to the battery, prevents for a fraction of the price the problem the jump starter fixes after the fact. If you bought one thing on this page, it would be here.
NOCO GENIUS1
1 A · 6 V et 12 V · compensation de température
One amp is little, and deliberately so: it maintains rather than charges. The thermal sensor adjusts voltage to temperature, which matters in an unheated garage — a charge voltage that is right at 20 °C is too low at −15 °C. It will also wake a battery that has fallen to 1 volt.
MOTOPOWER MP00207, 4 A
4 A · 6 V et 12 V · mode récupération
4 amps instead of one: it genuinely recharges a flat battery rather than merely holding it, at the same price. The right pick when the battery is already down rather than just idle — a winter vehicle, a boat, a stored snowmobile.
DEWALT DXAEWPC4, weatherproof
4 A · 12 V · boîtier étanche
The same job in a case that tolerates rain and snow. The one you leave connected outside or under a carport all winter, on the RV, the tractor or the trailer that will not move before May.
How to read the table
Trust the column that a maker could be held to. Engine displacement is checkable: if a unit claiming a 4 L diesel fails on a 4 L diesel, the claim is falsified. Peak amps cannot be falsified by a buyer, which is why the figure inflates.
Read starts per charge too, where it is given. The first attempt is never the problem. The fifth one is.